Centipede polymers and preparation and application in rubber compositions

ABSTRACT

The instant invention relates to poly(maleimide-co-alkenyl benzene) centipede polymer and a method for producing the polymer by reacting a poly(alkenyl benzene-co-maleic anhydride) in the presence of a primary amine in a substantially dry state. The invention is further directed to a process for blending the poly(maleimide-co-alkenyl benzene) centipede polymer with elastomeric polymers, in combination with, or in substitution of, conventional extender oils, to produce extended polymers having improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like.

BACKGROUND OF THE INVENTION

The polymerization of styrene and maleic anhydride by free radicalinitiation well known in the prior art. Similarly,poly(styrene-co-maleic anhydride) and poly(styrene-alt-maleic anhydride)polymers are well known. Further, imidization between a maleic anhydrideand a primary amine group is a commonly known chemical reaction.Publications which have recognized these reactions include: GermanPatent DE 4241538, assigned to Leuna-Werke A.-G; Japanese Patent JP94248017, assigned to Monsanto Kasel Kk.; and, Italian Patent EP 322905A2, assigned to Montedipe S.p.A. Various other non-patent publicationshave also recognized these reactions. Included among them are: L. E.Colleman, Jr., J. F. Bork, and H. Donn, Jr., J. Org. Chem., 24,185(1959); A. Matsumoto, Y. Oki, and T. Otsu, Polymer J.,23(3),201(1991); L. Haeussler, U. Wienhold, V. Albricht, and S.Zschoche, Themochim. Acta, 277, 14(1966); W. Kim, and K. Seo, Macromol.Rapid Commun., 17, 835(1996); W. Lee, and G. Hwong, J. Appl. Polym.Sci., 59, 599(1996); and, I. Vermeesch and G. Groeninckx, J. Appl.Polym. Sci., 53, 1356(1994).

The synthesis of monofunctional N-alkyl and N-aryl maleimides are alsowell known in the prior art. They have been extensively used to improvethe heat stability of homopolymers and especially copolymers preparedfrom vinyl monomers. Typically, the bulk resins comprise ABS(poly-(acrylonitrile-co-butadiene-co-styrene)) or a polyblend ofpoly-(acrylonitrile-co-butadiene) and poly-(styrene-co-acrylonitrile);PVC (poly(vinyl chloride)); SAN (poly(styrene-co-acrylonitrile)); PMMA(poly-(methyl methacrylate)); and the like. The maleimides can becopolymerized with other monomers such as acrylonitrile, butadiene,styrene, methyl methacrylate, vinyl chloride, vinyl acetate and manyother comonomers. A more preferred practice in the industry is toproduce copolymers of maleimides with other monomers such as styrene andoptionally acrylonitrile and to blend these with ABS and SAN resins. Inany event, the polymer compositions are adjusted so that the copolymersare fully compatible with the bulk resins (e.g., ABS and/or SAN) asshown by the presence of a single glass transition point (T_(g)) asdetermined by differential scanning calorimetry (DSC).

It has long been recognized that two or more polymers may be blendedtogether to form a wide variety of random or structured morphologies toobtain products that potentially offer desirable combinations ofcharacteristics. However, it may be difficult or even impossible inpractice to achieve many potential combinations through simple blendingbecause of some inherent and fundamental problem. Frequently, the twopolymers are thermodynamically immiscible, which precludes generating atruly homogeneous product. This immiscibility may not be a problem perse since often it is desirable to have a two-phase structure. However,the situation at the interface between these two phases very often doeslead to problems. The typical case is one of high interfacial tensionand poor adhesion between the two phases. This interfacial tensioncontributes, along with high viscosities, to the inherent difficulty ofimparting the desired degree of dispersion to random mixtures and totheir subsequent lack of stability, giving rise to gross separation orstratification during later processing or use. Poor adhesion leads, inpart, to the very weak and brittle mechanical behavior often observed indispersed blends and may render some highly structured morphologiesimpossible.

The abrasion resistance of rubbers generally increases with increasingmolecular weight. However, viscosity of the unvulcanized rubber alsoincreases with increase in molecular weight. Accordingly, inconventional practice a plasticizer (“extending oil”) is added to theunvulcanized rubber to lower its viscosity and to increase itsworkability to a point suitable for extrusion or other processing.

Kent et al in U.S. Pat. No. 3,528,936 and Cowperthwaite et al in U.S.Pat. No. 3,751,378 recognize that high molecular weight polymers ofbutadiene, etc., may be plasticized by addition of certain polyestermonomers. Both patents teach admixture of the monomer and polymertogether with an inorganic filler and other ingredients on an open millor in an internal mixer, i.e., “dry” blending with a filler.

It is particularly desirable to prepare a polymer useful as an oilsubstitute that performs the function of a polymer extender orplasticizer while enhancing beneficial polymer properties such astensile strength, maximum elongation, tear strength, damping properties.

OBJECTS OF THE INVENTION

It is an object of this invention to produce a poly(maleimide-co-alkenylbenzene) “centipede” polymer formed by imidizing a poly(alkenylbenzene-co-maleic anhydride). The “centipede” polymer has a highmolecular weight spine connected with many relatively short side chains.The length of the main chain usually equals or is longer than theentanglement length, which is herein defined theoretically as an orderof magnitude of 100 repeating units, while the length of the side chainsis much smaller than the entanglement length.

Still more specifically, it is an object of the invention to provide acentipede polymer formed by imidizing a poly(styrene-co-maleicanhydride) with a primary amine to form a poly(maleimide-co-styrene)polymer.

It is a further object of the present invention to produce a highmolecular weight poly(maleimide-co-alkenyl benzene) polymer formed bythe reaction product of a maleic anhydride contributed monomer unit of apoly(alkyl benzene-co-maleic anhydride) and a primary amine containingfrom 1 to 50 carbon atoms in the alkyl and alkoxy substituents in theprimary amine.

It is another object of the invention is to produce a high molecularweight poly(maleimide-co-alkenyl benzene) polymer useful as an oilsubstitute to be used as an a polymer extender that enhances beneficialpolymer properties such as tensile strength, maximum elongation, tearstrength, damping properties, and the like.

Finally, it is yet another object of the invention is to produce acentipede polymer that exhibits improved properties such as tensilestrength, maximum elongation, tear strength, damping properties, and thelike; that can be employed as a substitute for oils and/or plasticizersin the production of various other rubber compounds.

SUMMARY OF THE INVENTION

The present invention is broadly directed to poly(maleimide-co-alkenylbenzene) centipede polymer compositions formed by reacting apoly(alkenyl benzene-co-maleic anhydride) with a primary amine. It isfurther directed to a process for blending the poly(maleimide-co-alkenylbenzene) centipede polymer with elastomeric polymers, in combinationwith, or in substitution of, conventional extender oils, to produceextended polymers having improved properties such as tensile strength,maximum elongation, tear strength, damping properties, and the like.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is broadly directed to a polymer compositions of apoly(alkenyl benzene-co-maleimide) formed by reacting a poly(alkylbenzene-co-maleic anhydride) with a primary amine.

For the purposes of this invention, poly(alkenyl benzene-co-maleimide)and poly(alkyl benzene-co-maleic anhydride) are defined to encompassrandom and stereo-specific copolymers, including copolymers havingalternating alkenyl benzene and maleimide or maleic anhydridecontributed monomer units along the polymer backbone. Such alternatingstructure are typically described as poly(alkenyl benzene-adj-maleimide)and poly(alkyl benzene-adj-maleic anhydride), however, these polymersare encompassed herein within the descriptions poly(alkenylbenzene-co-maleimide) and poly(alkyl benzene-co-maleic anhydride)

Processes for forming poly(alkyl benzene-co-maleic anhydride) polymersare well known to those skilled in the art. The preparation of thecopolymers from electron donor monomers, such as styrene, and electronacceptor monomers, such as maleic anhydride, as a result of complexationof the electron acceptor monomers may be carried out in the absence aswell as in the presence of an organic free radical initiator in bulk, orin an inert hydrocarbon or halogenated hydrocarbon solvent such asbenzene, toluene, hexane, carbon tetrachloride, chloroform, etc. (N. G.Gaylord and H. Antropiusova, Journal of Polymer Science, Part B, 7, 145(1969) and Macromolecules, 2, 442 (1969); A. Takahashi and N. G.Gaylord, Journal of Macromolecular Science (Chemistry), A4, 127 (1970).

Poly(alkyl benzene-co-maleic anhydride) polymers are prepared byreacting monomers of alkenylbenzene with maleic anhydride. The preferredalkenyl benzene monomers used for forming the poly(alkylbenzene-co-maleic anhydride) polymer are styrene or α-methylstyrene.Suitable, but less preferred substitutes are: p-methylstyrene,4-phenylstyrene, m-methylstyrene, o-methylstyrene, p-tert-butylstyrene,dimethylstyrene, and combinations thereof

The poly(alkyl benzene-co-maleic anhydride) for use in the presentinvention is a polymer containing from about 5 to 99 mole percent ofmaleic anhydride monomer with the remainder being alkyl benzene monomer.The preferred poly(alkyl benzene-co-maleic anhydride) contains from 20to 50 mole percent of maleic anhydride monomer. The most preferredpoly(alkyl benzene-co-maleic anhydride) for use in the present inventionis poly(styrene-co-maleic anhydride) containing 50 mole percent ofmaleic anhydride monomer and 50 mole percent of styrene monomer. Thecomonomers, maleic anhydride and alkenyl benzene, can be randomly oralternatingly distributed in the chain, however, it is preferred to havethese comonomers alternating along the polymer backbone chain.

The poly(alkenyl benzene-co-maleic anhydride) has a molecular weightrange between about 1,000 and up to about 500,000 or higher, moretypically between about 10,000 and 500,000, and even more typicallybetween about 150,000 and 450,000, where the molecular weight isweight-average (“M_(w)”).

The poly(maleimide-co-alkenyl benzene) of the instant invention isformed by reacting a poly(alkyl benzene-co-maleic anhydride) in thepresence of a mono-primary amine at a temperature from about 100° C. toabout 300° C. and at a pressure from about slightly above vacuum toabout 20 atmospheres, under substantially dry conditions. The reactantsare preferably dry mixed in the absence of solvents in a suitable mixingapparatus such as a Brabender mixer equipped with Banbury blades. It ispreferable to purge the mixer with nitrogen prior to the charging of thereactants. The primary amine may be added in a singular charge or insequential partial charges into a reactor containing a charge ofpoly(alkyl benzene-co-maleic anhydride). Preferably the primary amine ischarged in ratio between 0.8 to 1.0 of moles of amine per monomercontributed units of maleic anhydride in the poly(alkylbenzene-co-maleic anhydride).

Suitable primary amine include but are not limited to: alkyl amines;alkyl benzyl amines; alkyl phenyl amines; alkoxybenzyl amines; alkylaminobenzoates; alkoxy aniline; and other linear primary aminescontaining from 1 to 50 carbon atoms, preferably 6 to 30 carbon atoms,in the alkyl and alkoxy substituents in these primary amines. It isunderstood that the alkyl and alkoxy substituents on the above discussedprimary amines can be linear or branched, preferably linear, andsaturated or unsaturated, preferably saturated. Exemplary, but notexclusive of such amines are: hexylamine, octylamine, dodecylamine andthe like.

The poly(maleimide-co-alkenyl benzene), preferably has a molecularweight range between about 1,000 and up to about 500,000 or higher, moretypically between about 10,000 and 500,000, and even more typicallybetween about 150,000 and 450,000, where the molecular weight isweight-average (“M_(w)”).

The poly(maleimide-co-alkenyl benzene) centipede polymers of the presentinvention can be employed as high damping additives and as analternative for plasticizers or oils in the formulation of variousrubber compounds or elastomeric polymers.

The centipede polymer of the present invention may be prepared by anymeans well known in the art for combining such ingredients, such asblending, milling or internal batch mixing. A rapid and convenientmethod of preparation comprises heating a mixture of the components to atemperature of about 50° C. to about 290° C.

The centipede polymers of this invention are preferably manufactured bymixing and dynamically heat-treating the components described above,namely, by melt-mixing. As for the mixing equipment, any conventional,generally known equipment such as an open-type mixing roll, closed-typeBanbury mixer, closed type Brabender mixer, extruding machine, kneader,continuous mixer, etc., is acceptable. The closed-type Brabender mixeris preferable, and mixing in an inactive gas environment, such asnitrogen or carbon dioxide, is also preferable.

In accordance with the present invention, the centipede polymercomposition of the present invention may be added as an extender or as aplasticizer to an elastomeric polymer in an amount ranging from about0.5-200 parts by weight per 100 parts by weight of a solid elastomericpolymer; preferably in an amount ranging from about 0.1 to about 50parts by weight of centipede polymer per 100 parts by weight of theelastomeric polymer to be extended. Most preferred amounts of addedcentipede polymer include from about 0.5 to about 20 parts of centipedepolymer per 100 parts of the elastomeric polymer. These parts by weightbeing effective plasticizing amounts of centipede polymer in elastomers.

Typical, but by no means limited to the types of thermodynamicallymiscible elastomeric polymers and copolymers that may be compatiblyblended and extended by the centipede polymers of the present inventionare elastomeric polymer containing formulations include but not limitedto: natural rubber, polyisoprene, polybutadiene, butadiene/styrenerubber (SBR), ethylene/propylene copolymer rubbers and blends thereofSBR and polybutadiene are preferred elastomers.

The use of poly(maleimide-co-alkenyl benzene) centipede polymersproduced according to the present invention as plasticizers forelastomeric polymers either alone or as a partial oil substituteincreases the damping properties of the elastomeric polymers overcomparable oil extended polymers. The use of the centipede polymers asan extender in elastomeric polymers also increases the tensile strength,the maximum elongation, tear strength and the travel at tearcharacteristics versus elastomers extended with a comparable amount ofoil extender.

Although the present invention also contemplates use of the instantcentipede polymers in combination with conventional extender oils, anembodiment contemplates the total substitution of conventional extendersby centipede polymers. Typical prior art extenders replaced by theinstant centipede polymers include extender oils and low molecularweight compounds or components. Such extender oils include those wellknown in the art such as naphthenic, aromatic and paraffinic petroleumoils and silicone oils. Examples of low molecular weight organiccompounds or components extenders in the compositions that may bereplaced by the centipede polymers of the present invention are lowmolecular weight organic materials having a number-average molecularweight of less than 20,000, preferable less than 10,000, and mostpreferably less than 5,000. Although there is no particular limitationto the material that the instant centipede polymers replace in prior artrubber compounds, the following is a list of examples of appropriatereplaceable materials: (1) softening agents, namely aromatic, naphthenicand paraffinic oil softening agents for rubbers or resins; and (2)plasticizers, namely plasticizers composed of esters including phthalic,mixed phthalic, aliphatic dibasic acid, glycol, fatty acid, phosphoricand stearic esters, epoxy plasticizers, other plasticizers for plastics;and (3) petroleum hydrocarbons, namely synthetic terpene resins,aromatic hydrocarbon resins, aliphatic hydrocarbon resins, aliphaticcyclic hydrocarbon resins, aliphatic or alicyclic petroleum resins,aliphatic or aromatic petroleum resins, polymers of unsaturatedhydrocarbons, and hydrogenated hydrocarbon resins. The instant centipedepolymers can be used to replace or partially replace one or more or allof these extender materials.

Additives useful in the compositions of the present application as wellknown in the rubber art. Stabilizers, antioxidants, conventionalfillers, reinforcing agents, reinforcing resins, pigments, fragrancesand the like are examples of some such additives. Specific examples ofuseful antioxidants and stabilizers include2-(2′-hydroxy-5′-methylphenyl) benzotriazole, nickeldibutyldithiocarbamate, zinc dibutyl dithiocarbamate, tris(nonylphenyl)phosphite, 2,6-di-t-butyl-4-methylphenol and the like. Exemplaryconventional fillers and pigments include silica, carbon black, titaniumdioxide, iron oxide and the like These compounding ingredients areincorporated in suitable amounts depending upon the contemplated use ofthe product, preferably in the range of 1 to 350 parts of additives orcompounding ingredients per 100 parts of the elastomeric polymer.

A reinforcement may be defined as the material that is added to a theelastomeric compositions to improve the strength of the centipedeextended elastomeric polymer. Most of these reinforcing materials areinorganic or organic products of high molecular weight. Various examplesinclude glass fibers, asbestos, boron fibers, carbon and graphitefibers, whiskers, quartz and silica fibers, ceramic fibers, metalfibers, natural organic fibers, and synthetic organic fibers. Otherelastomers and resins are also useful to enhance specific propertieslike damping properties, adhesion and processability. Examples of otherelastomers and resins include adhesive-like products including Reostomer(produced by Riken-Vinyl Inc.), hydrogenated polystyrene-(medium or high3,4) polyisoprene-polystyrene block copolymers such as Hybler (producedby Kurare Inc.), polynorbornenes such as Norsorex (produced by NipponZeon Inc.) and the like.

The centipede extended elastomer compositions obtained using themanufacturing method of this invention can be molded with equipmentconventionally used for molding thermoplastics. These centipede extendedelastomer compositions are suitable for extrusion molding, calendarmolding, and particularly injection molding. These compositions can bemixed in any conventional mixer such as a Brabender mixer, a Banburymixer or roll mill or extruder normally conducted within the temperaturerange of about 100° C. to about 300° C., preferably maintaining thecomposition above its melting point for a few minutes up to severalhours, preferably 10 to 40 minutes. A particularly useful technique isto add any fillers in the beginning of the mixing cycle in order to takemaximum advantage of heating time and to prevent surface bleeding andoverheating when forming the molded articles.

The centipede extended elastomeric polymer formulations may be molded inappropriate press ovens and the like to form products in the form ofextruded pellets, cut dices, preferably as small as possible sincesmaller pellets provide short heating times and better flow whenutilized in flow molding. Ground pellets may also be utilized.

In summary, the poly(maleimide-co-alkenyl benzene) centipede extendedelastomeric polymer formulations of the instant invention can be used inhigh temperature applications including uses in injection molding or inany other compositions typically for elastomeric properties. The use ofthe centipede polymers as an extender in elastomeric polymers increasesthe tensile strength, the maximum elongation, tear strength and thetravel at tear characteristics versus elastomers extended with acomparable amount of oil extender.

Damping is the absorption of mechanical energy by a material in contactwith the source of that energy. It is desirable to damp or mitigate thetransmission of mechanical energy from, e.g., a motor, engine, or powersource, to its surroundings. Elastomeric materials are often used forthis purpose. It is desirable that such materials be highly effective inconverting this mechanical energy into heat rather than transmitting itto the surroundings. It is further desirable that this damping orconversion is effective over a wide range of temperatures andfrequencies commonly found near motors, automobiles, trucks, trains,planes, and the like.

A convenient measurement of damping is the determination of a parametercalled tan δ. A forced oscillation is applied to a material at frequencyf and the transmitted force and phase shift are measured. The phaseshift angle delta is recorded. The value of tan δ is proportional to theratio of (energy dissipated)/(energy stored). The measurement can bemade by any of several commercial testing devices, and may be made by asweep of frequencies at a fixed temperature, then repeating that sweepat several other temperatures, followed by the development of a mastercurve of tan δ vs. frequency by curve alignment. An alternate method isto measure tan δ at constant frequency (such as at 10 hz) over atemperature range. We have defined an unfilled material as useful fordamping when tan δ>˜0.3 over at least a 4 decade range, preferably a 6decade range of frequency.

It is further important that this high degree of absorption of energy beaccompanied by good mechanical and thermal stability, as the partprepared from the subject centipede extended polymers will be cycledthrough various environments and repeatedly such to various forces ofcompression, tension, bending, and the like.

The compositions of the present invention are favorably used in themanufacturing of any product in which the following properties areadvantageous: a high degree of softness, heat resistance, decentmechanical properties, elasticity and/or high damping. The compositionsof the present invention can be used in all industry fields, inparticular, in the fabrication of automotive parts, tire tread rubbers,household electrical appliances, industrial machinery, precisioninstruments, transport machinery, constructions, engineering, andmedical instruments.

Representative examples of the uses of the instant centipede extendelastomeric polymers are damping materials, and vibration restrainingmaterials. These uses involve connecting materials such as sealingmaterials, packing, gaskets and grommets, supporting materials, such asmounts, holders and insulators, and cushion materials such as stoppers,cushions, and bumpers. These materials are also used in equipmentproducing vibration or noise and household electrical appliances, suchas in air-conditioners, laundry machines, refrigerators, electric fans,vacuums, driers, printers and ventilator fans. Further, these materialsare also suitable for impact absorbing materials in audio equipment andelectronic or electrical equipment, sporting goods and shoes.

In the following, the present invention will be described in more detailwith reference to non-limitative examples. The following examples andtables are presented for purposes of illustration only and are not to beconstrued in a limiting sense.

Preparation of Centipede Polymer EXAMPLE 1

A nitrogen purged Brabender mixer (˜310 gram capacity) equipped with aBanbury blade was initially set to 30 rpm and the temperature was set to165° C. The mixer was then charged with 150 g of poly(styrene-alt-maleicanhydride) (obtained from Aldrich Chemical Company of 1001 West SaintPaul Avenue, Milwaukee, Wis. Catalog Number: 18,293-1, CAS Number:9011-13-6)(M_(n)=350,000) and 34.5 g of dodecyl amine (obtained fromAldrich, 98% purity). The contents of the mixer was then agitated for 10minutes and then a charge of another 34.5 g of dodecyl amine was addedto the mixer. This procedure was repeated 3 times until a total of 138 gof dodecyl amine had been added to the mixer. After 30 minutes ofcontinuous mixing, the agitation speed was reset to 60 rpm and thetemperature was reset to 205° C. Agitation was continued for anadditional 65 minutes. Agitation was thereafter reset to 15 rpm and theheating element of the mixer was turned off, and the polymer mass withinthe mixer was permitted to cool down to 150° C. at a rate of ˜4° C./min.The agitation was then stopped and the centipede polymer product masswas then removed from the mixer.

IR absorption peaks characteristic of the centipede polymer mass werenoted substantially only at 704 cm⁻¹, 1701 cm⁻¹, 1772 cm⁻¹, 2852 cm⁻¹and 2923 cm⁻¹. The ratio of the intensities was observed at I₂₉₂₃ toI₁₇₀₁≡0.8. Further, an NGR analysis (¹H and ¹³C) indicated that theimidization reaction within the product mass had achieved a 100%completion. It was not possible to define the T_(g) value since thecharacteristic T_(g) transition is very broad when using DSC. No stepchange in heat capacity was noted (i.e., ΔCp. vs. Temperature).

EXAMPLE 2

The same nitrogen purged Brabender mixer (˜310 g capacity) equipped witha Banbury blade of foregoing Example 1 was initially set to 30 rpm andthe temperature was set to 80° C. The mixer was then charged with 150 gof poly(styrene-alt-maleic anhydride) (obtained from Aldrich,M_(n)=350K) and 96 g of octyl amine (obtained from Aldrich, 99% purity).After 5 minutes, the mixture was permitted to heat up at a rate of 4°C./min. Once the temperature of the mixture reached 140° C., theagitation was discontinued. When the temperature of the mixture rose to250° C., the heating element of the mixer was set to isothermal mode andthe agitation was resumed at a speed of 30 rpm. After 5 minutes ofcontinuous mixing, the agitation speed was reset to 70 rpm and thetemperature was reset to 210° C. Agitation was continued for anadditional 65 minutes. The heating element of the mixer was then turnedoff, and the polymer mass within the mixer was permitted to cool down ata rate of ˜4° C./min. The agitation was then turned off and thecentipede polymer product mass, while at temperature of 160° C., wasthen removed from the mixer.

IR absorption peaks characteristic of the centipede polymer mass werenoted substantially only at 705 cm⁻¹, 1701 cm⁻¹, 1770 cm⁻¹, 2855 cm⁻¹and 2926 cm⁻¹. The ratio of the intensities was observed at I₂₉₂₆ toI₁₇₀₁≡0.55. Further, an NGR analysis (¹H and ¹³C) indicated that theimidization reaction within the product mass had achieved a 100%completion (i.e., no traces of maleic anhydride peaks at 1770 cm⁻¹ and1855 cm⁻¹; and, amino group peaks at 3330 cm⁻¹). Although the DSCcharacteristic T_(g) transition was very broad, between −50° C. to 75°C., the T_(g) was estimated at 60° C.

EXAMPLES 3-9 Application of Centipede Polymers in Rubber Compounds

In Examples 3 to 9, rubber compositions were prepared according to theformulation as displayed in parts by weight as shown in Table 1. InExamples 4 to 8 the centipede polymer of Example 1 was used to at leastpartially replace that amount of aromatic oil normally used, as shown inTable 3. Although the respective amounts of aromatic oil and centipedepolymer were varied, the sum of the respective amounts (18.25 parts byweight) was kept constant in all compounds. The rubber compound used inthe formulation in Table 1 was an oil-extended high-styrene SBR (20 phraromatic oil) which contained 33% bound styrene with a T_(g)=−47° C. Thecis-BR used was a high-cis polybutadiene with a cis content=96%. In eachsample, the components were kneaded by the method indicated in Table 2.The final stock was sheeted and molded at 165° C. for ˜15 minutes. Foreach of the sample vulcanized rubber compounds of Examples 3 to 9,measurements of the tensile strength; tear strength; and, hysteresisloss were taken. The results of these measurements appears in Table 3.Measurements of tensile strength were based upon the conditions ofASTM-D 412 at 22° C. Test specimen geometry was taken in the form of aring having a width of 0.05 inches and a thickness of 0.075 inches. Thespecimen was tested at a specific gauge length of 1.0 inches. Themeasurement of tear strength is based on conditions of ASTM-D 624 at170° C. Test specimen geometry was also taken in the form of a nickedring in accordance with the conditions defined in ASTM-624-C. Thespecimen was tested at the specific gauge length of 1.750 inches. Thehysteresis loss was measured with a Dynastat Vicoelastic Analyzer. Thetest specimen geometry was also taken in the form of a cylinder of alength of 0.6125 inches and a diameter of 0.375 inches. The specimen wastested at a frequency of 1 Hz and a temperature of 50° C. A static massof 2.0 Mpa and a dynamic mass of 2.50 MPa were applied for the test. Ascan be seen in Table 3, the rubber compositions of Examples 4-8exhibited very well balanced: tensile strengths; tear strengths; and,damping properties. An evaluation of the resistance of the samples wasobtained by weighing the amount of wear. Assuming all considerationswere based upon the same modulus condition, no significant differenceswere observed between the test samples and the comparative samples.

Accordingly, it was concluded that the polymers developed according tothe instant invention (as shown in samples 1-2) are suitable as highdamping additives in rubber compounds. It was further concluded thatthese polymers could be used as alternative substitutes for oils and/orplasticizers.

TABLE 1 Styrene-Butadiene Rubber (SBR, Duradene 753) 96.80 ButadieneRubber (cis-BR, Diene 600) 20.00 Carbon Black (ISAF) 70.00 Aromatic Oil18.25 Stearic Acid 2.00 Wax 1.50 Antioxidant [N-(1,3dimethybutyl)-N′-phenyl 0.95 -p-phenylene-diamine] Sulfur 1.70Accelerator [N-tert-butyl-benzothiazolesulfenamine] 0.80 Zinc Oxide 2.00Antioxidant [polymerized 1,2-dihydro- 0.22 2,2,4-trimethylquioline]Accelerator (benzothiazyl disulfide) 0.20 Accelerator(tetra-methylthiuram monosulfide) 0.20

TABLE 2 Mixer 310 g Brabender Agitation Speed 60 rpm Mater Batch StageInitial Temperature 110° C.  0 sec charging polymers 30 sec chargingcarbon black and all pigments  5 min drop Remill Batch Stage InitialTemperature 110° C. 0 sec charging mater batch stock 4 min drop FinalBatch Stage Initial Temperature 75° C.  0 sec charging remilled stock 30sec charging curing agent and accelerators 80 sec drop

TABLE 2 Mixer 310 g Brabender Agitation Speed 60 rpm Mater Batch StageInitial Temperature 110° C.  0 sec charging polymers 30 sec chargingcarbon black and all pigments  5 min drop Remill Batch Stage InitialTemperature 110° C. 0 sec charging mater batch stock 4 min drop FinalBatch Stage Initial Temperature 75° C.  0 sec charging remilled stock 30sec charging curing agent and accelerators 80 sec drop

Table 3 shows a series of seven examples wherein a damping polymer thatwas extended only by conventional extender oils in comparative Examples3(comp) and 9(comp)), was compared to the same damping polymer extendedwith varying proportions of the instant centipede polymer toconventional extender oils while maintaining a constant total extenderoil weight proportion of 18.25 parts by weight of extender. For example,Example 3 contained 18.25 parts by weight of aromatic oil while Example4 contained 13.25 parts by weight of aromatic oil and 5 parts by weightof centipede polymer as prepared in Example 1. Substantial improvementscan be noted in the examples that were partially extended with thecentipede polymer of the present invention, with respect to tensilestrength, tear strength, travel at tear and tan δ at 50° C.

Although the invention has been described with reference to particularmeans, materials and embodiments it is to be understood that theinvention is not limited to the particulars disclosed and extends to allequivalents within the scope of the claims.

We claim:
 1. A cured elastomeric composition comprising: an elastomer0.1-50 pbw reaction product per 100 parts of said elastomer, saidreaction product consisting essentially of a fully imidized polymercomprising units contributed from an alkenyl benzene and maleicanhydride, reacted with a primary monoamine; optionally, an inorganicfiller, additive, or compounding ingredient, and, optionally, one ormore of a softening agent, plasticizer, tackifier, oligomer, lubricant,petroleum hydrocarbon, silicone oil, aromatic oil, naphthenic oil, andparaffinic oil.
 2. The composition of claim 1 wherein said compositionhas a tan δ in the range of about 1 to about 0.10 over a temperaturerange of 30° to 100° C.
 3. The composition of claim 1 wherein saidelastomer comprises natural rubber, polyisoprene, polybutadiene,styrene/butadiene rubber, or ethylene/propylene copolymer rubber.
 4. Thecomposition of claim 1 wherein said alkenyl benzene comprises styrene,α-methylstyrene, tert-butylstyrene, p-methylstyrene, 4-phenylstyrene,m-methylstyrene, o-methyl-styrene, or dimethylstyrene.
 5. Thecomposition of claim 1 wherein said primary monoamine comprises an alkylamine, alkyl benzyl amine, alkyl phenyl amine, alkoxybenzyl amine, alkylaminobenzoate, or alkoxy aniline.
 6. The composition of claim 1 whereinsaid reaction product comprises a main chain with side chains shorterthan the entanglement length and comprises from about 20 to 50 molepercent units contributed from maleic anhydride.
 7. A vibration damperor tire tread comprising a cured elastomeric composition comprising: anelastomer; 0.1-50 pbw reaction product of a fully imidized polymercomprising units contributed from an alkenyl benzene and maleicanhydride, reacted with a primary monoamine, per 100 pbw of saidelastomer; optionally, an inorganic filler, additive, or compoundingingredient; and optionally, one or more of a softening agent,plasticizer, tackifier, oligomer, lubricant, petroleum hydrocarbon,silicone oil, aromatic oil, naphthenic oil, and paraffinic oil.
 8. Acured elastomeric composition comprising: a) an elastomer b) 0.1-50 pbwfully imidized copolymer per 100 pbw said elastomer, said copolymercomprising units contributed from 1) an alkenyl benzene and 2) amaleimide, said copolymer acting as an extender material for saidelastomer; and c) optionally an inorganic filler, additive, orcompounding ingredient, said composition being free of conventionalextenders for elastomers.
 9. The composition of claim 8 wherein saidcomposition has a tan δ in the range of about 1 to about 0.10 over atemperature range of 30° to 100° C.
 10. The composition of claim 8wherein said copolymer is linear.
 11. The composition of claim 9 whereinsaid elastomer comprises natural rubber, polyisoprene, polybutadiene,styrene/butadiene rubber, or ethylene/propylene copolymer rubber. 12.The composition of claim 9 wherein said alkenyl benzene comprisesstyrene, α-methylstyrene, tert-butylstyrene, p-methylstyrene,4-phenylstyrene, m-methylstyrene, o-methyl-styrene, or dimethylstyrene.13. A vibration damper or tire tread comprising an elastomericcomposition comprising: an elastomer 0.1-50 pbw fully imidized copolymerper 100 pbw said elastomer, said copolymer comprising units contributedfrom an alkenyl benzene, and a maleimide, said copolymer acting as anextender material for said elastomer; and optionally, an inorganicfiller, additive, or compounding ingredient; said composition being freeof conventional extenders for elastomers.
 14. A cured elastomericcomposition comprising: a) an elastomer; b) 0.1-50 pbw fully imidizedcopolymer per 100 pbw said elastomer, said copolymer comprising unitscontributed from 1) an alkenyl benzene and 2) a maleimide said copolymerhaving a weight average molecular weight of from about 150,000 to450,000; and c) optionally, an inorganic filler additive, or compoundingingredient; and d) optionally, one or more of a softening agent,plasticizer, tackifier, oligomer, lubricant, petroleum hydrocarbon,silicone oil, aromatic oil, naphthenic oil, and paraffinic oil.
 15. Thecomposition of claim 14 wherein said composition has a tan δ in therange of about 1 to about 0.10 over a temperature range of 30° to 100°C.
 16. The composition of claim 14 wherein said copolymer is linear. 17.The composition of claim 14 wherein said elastomer comprises naturalrubber, polyisoprene, polybutadiene, styrenelbutadiene rubber, orethylene/propylene copolymer rubber.
 18. The composition of claim 14wherein said alkenyl benzene comprises styrene, α-methylstyrene,tert-butylstyrene, p-methylstyrene, 4-phenylstyrene, m-methylstyrene,o-methyl-styrene, or dimethylstyrene.
 19. A vibration damper or tiretread comprising an elastomeric composition comprising: an elastomer;0.1-50 pbw fully imidized copolymer per 100 pbw said elastomer, saidcopolymer comprising units contributed from an alkenyl benzene and amaleimide, said copolymer having a weight average molecular weight offrom about 150,000 to 450,000; and optionally, an inorganic filler,additive, or compounding ingredient; and optionally, one or more of asoftening agent, plasticizer, tackifier, oligomer, lubricant, petroleumhydrocarbon, silicone oil, aromatic oil, naphthenic oil, and paraffinicoil.
 20. A elastomeric composition comprising: a curing agent; anelastomer; 0.1-50 pbw poly(alkenylbenzene-co-maleimide) per 100 parts ofsaid elastomer; optionally, an inorganic filler, additive, orcompounding ingredient; and, optionally, one or more of a softeningagent, plasticizer, tackifier, oligomer, lubricant, petroleumhydrocarbon, silicone oil, aromatic oil, naphthenic oil, and paraffinicoil.
 21. The composition of claim 20 wherein saidpoly(alkenyl-co-maleimide) is present in the range of about 0.5 to about20 pbw per 100 parts of said elastomer.
 22. The composition of claim 20wherein said curing agent comprises sulfur.